This mount slots into the keyhole/teardrop on the back and provides an eye to use on hooks, screwheads, that kind of thing. Obviously you shouldn't use this where it is exposed to high winds. 

Two versions are supplied, a regular one and an “extended” one which goes down further in the back. The latter is intended so you can add a peg and make it sit “upright” if your hook brings it out from the wall, as show in the picture. This peg is just a cylinder and glued to the mount; use tinker cad or the F3D file included. You can also just use the regular version.

A little support is required because of the geometry of the keyhole design, but it should be relatively easy to remove.